Many types of communication cables, such as twisted pair communication cables, incorporate shields in order to mitigate the effects of noise, interference, and crosstalk. Continuous shields, such as metallic shields that circumferentially encase conductors, must typically be grounded at both ends to prevent the shield from inadvertently carrying a voltage along its length that can lead to a shock hazards. Continuous shields can also set up standing waves of electromagnetic energy based on signals received from nearby energy sources. A standing wave can radiate electromagnetic energy, somewhat like an antenna, that may interfere with wireless communication devices or other sensitive equipment operating nearby. In order to address the limitations of continuous shields, segmented or discontinuous shields have been incorporated into certain cables. These segmented shields typically include metallic patches formed on a polymeric film, and electrical discontinuity (i.e., spaces or gaps) is maintained between the metallic patches. Thus, the patches function as an electromagnetic shield; however, it is not necessary to ground the shields during cable installation.
Current segmented shield designs are typically manufactured by applying a continuous metallic layer to a dielectric layer, and then either “kiss-cutting” or etching gaps or spaces through the metallic layer. In a kiss-cutting process, the metallic layer is cut with a blade or laser without also penetrating or cutting the dielectric layer, and small sections of the metallic layer are removed. This is a relatively expensive process that requires special tooling and processing expertise. In an etching process, an acid or other agent is utilized to selectively remove portions of the metallic layer in order to form gaps or spaces. These conventional manufacturing processes are typically time-consuming, resulting in slower processing line speeds and an overall higher cost. For example, certain conventional discontinuous shield manufacturing processes typically operate at line speeds of approximately fifteen meters per minute. As a result of the relatively slow processing speeds, the discontinuous shields cannot be integrated into cables in an in-line manner.
In another conventional process, slits are cut into a metallic foil layer without removing any of the foil and without cutting the dielectric layer. These slits are cut across the entire foil width in order to form discontinuities. However, there is a possibility that the cut foil edges may contact one another, for example, when the shield structure is bent. There is also a possibility that electrical current may arc across the slits during use.
Accordingly, there is an opportunity for improved methods, techniques, and/or systems for forming or manufacturing discontinuous shield structures. There is additionally an opportunity for improved discontinuous shield manufacturing methods and/or systems that may be carried out in a relatively faster and cost-effective manner. There is also an opportunity for discontinuous shield manufacturing methods and/or systems that may be conducted in-line with a cable assembly process. Further, there is an opportunity for improved discontinuous shield structures that may be incorporated into cables.